Android中GridView拖拽的效果

最
近看到联想，摩托罗拉等，手机launcher中有个效果，进入mainmenu后，里面的应用程序的图标可以拖来拖去，所以我也参照网上给的代码，写了
一个例子。还是很有趣的，实现的流畅度没有人家的那么好，我只是模仿这种效果，我写的这个拖拽是两个图标之间进行交换，所以，当从一行的某个位置，换到下
一行的另一列的时候，发现有好几个图标都改变位置了，因为是相邻两个交换位置，所以每经过相邻的图标的时候都改变位置。先弄个雏形，以后再更新优化。

转载请标明出处：http://blog.csdn.net/wdaming1986/article/details/7436881

先看几张效果图，再来研究代码：

横行拖拽：

纵向拖拽的效果图：

下面贴上代码---->在GragGridViewApp-4-7这个工程里面：

1、在包com.cn.daming.adapter中，有三个类----->

1.1、DragAdapter.java这个类中的代码如下：

[java] view plain copy print ?

package com.cn.daming.adapter;

import java.util.ArrayList;

import java.util.Collections;

import android.content.Context;

import android.view.View;

import android.view.ViewGroup;

import android.widget.BaseAdapter;

public abstract class DragAdapter extends BaseAdapter {

protected Context mContext;

protected ArrayList<DragMessage> mlist;

public DragAdapter(Context mContext, ArrayList<DragMessage> mlist) {

this.mContext = mContext;

this.mlist = mlist;

}

public int getCount() {

if (this.mlist != null) {

return this.mlist.size();

}

return 0;

}

public DragMessage getItem(int position) {

return (DragMessage)this.mlist.get(position);

}

public long getItemId(int position) {

return 0;

}

public void addMsg(DragMessage msg){

this.mlist.add(msg);

}

final void reFlag(){

for (DragMessage msg : this.mlist) {

msg.flag = 0;

}

notifyDataSetChanged();

}

final void swap(int srcPosition, int dragPosition){

Collections.swap(this.mlist, srcPosition, dragPosition);

notifyDataSetChanged();

}

final void setFlag(int position, int flag){

getItem(position).flag = flag;

notifyDataSetChanged();

}

public abstract View getView(int position, View convertView, ViewGroup parent);

}

1.2、DragMessage.java这个类中的代码如下：

[java] view plain copy print ?

package com.cn.daming.adapter;

public class DragMessage {

public static final int MOVE_FLAG = 1;

public static final int STATIC_FLAG = 0;

public int flag = 0;

}

1.3、GragGridView.java核心类中的代码如下：

[java] view plain copy print ?

package com.cn.daming.adapter;

import android.content.Context;

import android.graphics.Bitmap;

import android.graphics.Color;

import android.graphics.PixelFormat;

import android.graphics.drawable.Drawable;

import android.os.Handler;

import android.os.Looper;

import android.os.Message;

import android.util.AttributeSet;

import android.util.Log;

import android.view.Gravity;

import android.view.MotionEvent;

import android.view.View;

import android.view.ViewGroup;

import android.view.WindowManager;

import android.widget.AdapterView;

import android.widget.GridView;

import android.widget.ImageView;

public class GragGridView extends GridView{

private ImageView dragImageView;//拖动item的preview

private WindowManager windowManager;

private WindowManager.LayoutParams windowParams;

private int dragSrcPosition; //开始拖拽的位置

private int dragPosition; // 结束拖拽的位置

private int dragPointX;//相对于item的x坐标

private int dragPointY;//相对于item的y坐标

private int dragOffsetX;

private int dragOffsetY;

private int dragImageId;

private int itemHeight;

private int itemWidth;

private int moveHeight = 0;

private int upScrollBounce;

private int downScrollBounce;

private int dragColor = Color.GRAY;

private int changePosition = -1;

private long scrollDelayMillis = 10L;

private int middleX;

private int middleY;

private boolean isDrag = false;

private RefreshHandler scrollDelayUp = new RefreshHandler(Looper.getMainLooper(), true);

private RefreshHandler scrollDelayDown = new RefreshHandler(Looper.getMainLooper(), false);

private int scrollHeight = 4;

private int maxSH = 20;

private int minSH = 4;

public void setMoveHeight(int height) {

this.moveHeight = height;

}

public void setDragColor(int color) {

this.dragColor = color;

}

public void setDragImageId(int id) {

this.dragImageId = id;

}

public GragGridView(Context context, AttributeSet attrs) {

super(context, attrs);

}

@Override

public boolean onInterceptTouchEvent(MotionEvent ev) {

if (ev.getAction() == MotionEvent.ACTION_DOWN) {

int x = (int)ev.getX();

int y = (int)ev.getY();

this.dragSrcPosition = this.dragPosition = pointToPosition(x, y);

if (this.dragPosition == -1) {

return super.onInterceptTouchEvent(ev);

}

ViewGroup itemView = (ViewGroup)getChildAt(this.dragPosition -

getFirstVisiblePosition());

//得到当前点在item内部的偏移量即相对于item左上角的坐标

this.itemHeight = itemView.getHeight();

this.dragPointX = (x - itemView.getLeft());

this.dragPointY = (y - itemView.getTop());

this.dragOffsetX = (int)(ev.getRawX() - x);

this.dragOffsetY = (int)(ev.getRawY() - y);

View dragger = itemView.findViewById(this.dragImageId);

if ((dragger != null) && (x > dragger.getLeft()&& x < dragger.getRight()) &&

(y > dragger.getTop() && y < dragger.getBottom())) {

if(this.moveHeight <= 0 || (this.moveHeight >= getHeight()/2)) {

this.upScrollBounce = (getHeight() / 3);

this.downScrollBounce = (getHeight() * 2 / 3);

} else {

this.upScrollBounce = this.moveHeight;

this.downScrollBounce = (getHeight() - this.moveHeight);

}

//解决问题3

//每次都销毁一次cache，重新生成一个bitmap

itemView.destroyDrawingCache();

itemView.setDrawingCacheEnabled(true);

Drawable background = itemView.getBackground();

itemView.setBackgroundColor(this.dragColor);

Bitmap bitmap = Bitmap.createBitmap(itemView.getDrawingCache());

itemView.setBackgroundDrawable(background);

//建立item的缩略图

startDrag(bitmap, x, y);

}

return false;

}

return super.onInterceptTouchEvent(ev);

}

@Override

public boolean onTouchEvent(MotionEvent ev) {

if ((this.dragImageView != null) && (this.dragPosition != -1)) {

int action = ev.getAction();

int moveY = (int)ev.getY();

int moveX = (int)ev.getX();

switch(action) {

case MotionEvent.ACTION_UP:

int upX = (int)ev.getX();

int upY = (int)ev.getY();

stopDrag();

onDrop(upX, upY);

break;

case MotionEvent.ACTION_MOVE:

if (moveX <= 0)

this.middleX = 0;

else if (moveX >= getWidth())

this.middleX = getWidth();

else {

this.middleX = moveX;

}

if (moveY <= 0)

this.middleY = 0;

else if (moveY >= getHeight())

this.middleY = getHeight();

else {

this.middleY = moveY;

}

dragPositionChanged();

onDrag(moveX, moveY);

}

return true;

}

return super.onTouchEvent(ev);

}

private void onDrag(int x, int y) {

if (this.dragImageView != null) {

this.windowParams.alpha = 0.8F;

if (this.middleX - this.dragPointX <= 0)

this.windowParams.x = this.dragOffsetX;

else if (this.middleX - this.dragPointX >= getWidth() - this.itemWidth)

this.windowParams.x = (getWidth() - this.itemWidth + this.dragOffsetX);

else {

this.windowParams.x = (this.middleX - this.dragPointX + this.dragOffsetX);

}

if (this.middleY - this.dragPointY <= 0)

this.windowParams.y = this.dragOffsetY;

else if (this.middleY - this.dragPointY >= getHeight() - this.itemHeight)

this.windowParams.y = (getHeight() - this.itemHeight + this.dragOffsetY);

else {

this.windowParams.y = (this.middleY - this.dragPointY + this.dragOffsetY);

}

this.windowManager.updateViewLayout(this.dragImageView, this.windowParams);

}

int tempPosition = pointToPosition(this.middleX, this.middleY);

Log.v("daming", "GragGridView ---> 177 tempPosition == "+tempPosition);

if (tempPosition != -1) {

this.dragPosition = tempPosition;

}

if ((y >= this.upScrollBounce) && (y <= this.downScrollBounce)) {

this.isDrag = false;

return;

}

if (y < this.upScrollBounce) {

float a = this.upScrollBounce - this.middleY;

float b = this.upScrollBounce;

float c = a / b;

this.scrollHeight = (int)(c * (this.maxSH - this.minSH) + this.minSH);

this.isDrag = true;

this.scrollDelayUp.sleep(0L);

} else if (y > this.downScrollBounce) {

float a = this.middleY - this.downScrollBounce;

float b = this.upScrollBounce;

float c = a / b;

this.scrollHeight = (int)(c * (this.maxSH - this.minSH) + this.minSH);

this.isDrag = true;

this.scrollDelayDown.sleep(0L);

}

}

private void startDrag(Bitmap bm, int x, int y) {

stopDrag();

this.windowParams = new WindowManager.LayoutParams();

//Gravity.TOP|Gravity.LEFT;这个必须加

this.windowParams.gravity = Gravity.TOP|Gravity.LEFT;

//得到preview左上角相对于屏幕的坐标

this.windowParams.x = (x - this.dragPointX + this.dragOffsetX);

this.windowParams.y = (y - this.dragPointY + this.dragOffsetY);

//设置拖拽item的宽和高

this.windowParams.width = WindowManager.LayoutParams.WRAP_CONTENT;

this.windowParams.height = WindowManager.LayoutParams.WRAP_CONTENT;

this.windowParams.flags = WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE

| WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE

| WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON

| WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN;

this.windowParams.format = PixelFormat.TRANSLUCENT;

this.windowParams.windowAnimations = 0;

ImageView imageView = new ImageView(getContext());

imageView.setImageBitmap(bm);

this.windowManager = ((WindowManager)getContext().getSystemService(Context.WINDOW_SERVICE));//“window”

this.windowManager.addView(imageView, this.windowParams);

this.dragImageView = imageView;

}

private void stopDrag() {

if (this.dragImageView != null) {

this.windowManager.removeView(this.dragImageView);

this.dragImageView = null;

}

this.changePosition = -1;

this.isDrag = false;

}

private void dragPositionChanged(){

DragAdapter adapter = (DragAdapter)getAdapter();

if (this.changePosition != this.dragPosition) {

if (this.changePosition == -1)

{

this.changePosition = this.dragPosition;

adapter.setFlag(this.changePosition, 1);

return;

}

adapter.swap(this.changePosition, this.dragPosition);

this.changePosition = this.dragPosition;

}

}

public void setMaxSH(int sh){

this.maxSH = sh;

}

public void setMinSH(int sh){

this.minSH = sh;

}

private void onDrop(int x, int y){

//为了避免滑动到分割线的时候，返回-1的问题

int tempPosition = pointToPosition(x, y);

if(tempPosition!=INVALID_POSITION){

dragPosition = tempPosition;

}

//超出边界处理

if(y<getChildAt(0).getTop()){

//超出上边界

dragPosition = 0;

}else if(y>getChildAt(getChildCount()-1).getBottom()||

(y>getChildAt(getChildCount()-1).getTop()&&x>getChildAt(getChildCount()-1).getRight())){

//超出下边界

dragPosition = getAdapter().getCount()-1;

}

//数据交换

if(dragPosition!=dragSrcPosition&&dragPosition>-1&&dragPosition<getAdapter().getCount()){

DragAdapter adapter = (DragAdapter)getAdapter();

adapter.reFlag();

}

// DragAdapter adapter = (DragAdapter)getAdapter();

// adapter.reFlag();

}

private void actDown(){

int tempPosition = pointToPosition(this.middleX, this.middleY);

if (tempPosition != AdapterView.INVALID_POSITION) {

this.dragPosition = tempPosition;

}

dragPositionChanged();

}

private void actUp(){

int tempPosition = pointToPosition(this.middleX, this.middleY);

if (tempPosition != AdapterView.INVALID_POSITION) {

this.dragPosition = tempPosition;

}

dragPositionChanged();

}

class RefreshHandler extends Handler {

boolean isUp;

public RefreshHandler(Looper looper, boolean isUp){

super(looper);

this.isUp = isUp;

}

public RefreshHandler(Looper l) {

super(l);

}

public void handleMessage(Message msg){

if (GragGridView.this.isDrag) {

if (this.isUp)

GragGridView.this.actUp();

else {

GragGridView.this.actDown();

}

sleep(GragGridView.this.scrollDelayMillis);

}

}

public void sleep(long delayMillis) {

sendMessageDelayed(obtainMessage(0), delayMillis);

}

}

}

2、在包com.cn.daming.draggridview中，有两个类---->

2.1、GragGridViewAppActivity.java入口类中的代码：

[java] view plain copy print ?

package com.cn.daming.draggridview;

import java.util.ArrayList;

import android.app.Activity;

import android.content.Context;

import android.graphics.Color;

import android.graphics.drawable.Drawable;

import android.os.Bundle;

import android.view.LayoutInflater;

import android.view.View;

import android.view.ViewGroup;

import android.widget.ImageView;

import android.widget.TextView;

import com.cn.daming.adapter.DragAdapter;

import com.cn.daming.adapter.DragMessage;

import com.cn.daming.adapter.GragGridView;

public class GragGridViewAppActivity extends Activity {

private MyAdapter myAdapter;

private ArrayList<DragMessage> mlist = new ArrayList<DragMessage>();

private GragGridView mGridView;

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.drag_grid_activity);

initDate();

mGridView = (GragGridView)findViewById(R.id.drag_grid);

myAdapter = new MyAdapter(this, mlist);

mGridView.setAdapter(myAdapter);

//设置触发拖动的区域，用一个ImageView来设置,这个必须设置

mGridView.setDragImageId(R.id.grag_grid_item_view);

//以下这些都做了相应的处理，不设置没关系，而且效果也不错

//设置拖动浮项的背景色

// mListView.setDragColor(Color.RED);

//设置滚动的最大像素

// mListView.setMaxSH(sh);

//设置滚动的最小像素

// mListView.setMinSH(sh);

//设置滚动区的高度（2*height应该小于ListView自己的高度）

// mListView.setMoveHeight(height);

}

private void initDate(){

for (int i = 1; i <= 100; i++) {

MyMessage msg = new MyMessage();

String str = "DM_" + i;

msg.msg = str;

mlist.add(msg);

}

}

class MyAdapter extends DragAdapter{

Drawable background;

public MyAdapter(Context mContext, ArrayList<DragMessage> mlist) {

super(mContext, mlist);

}

@Override

public View getView(int position, View convertView, ViewGroup parent) {

View view = convertView;

ViewHolder holder = null;

if (view == null) {

view = LayoutInflater.from(mContext).inflate(

R.layout.drag_grid_item, null);

holder = new ViewHolder();

holder.tv = (TextView) view

.findViewById(R.id.drag_grid_item_text);

holder.iv = (ImageView) view

.findViewById(R.id.drag_grid_item_image);

view.setTag(holder);

} else {

holder = (ViewHolder) view.getTag();

}

holder.tv.setText(((MyMessage)getItem(position)).msg);

holder.iv.setBackgroundResource(R.drawable.title2);

if(background == null){

background = view.getBackground();}

if(getItem(position).flag == DragMessage.MOVE_FLAG){

view.setBackgroundColor(Color.GRAY);

}

else{

view.setBackgroundDrawable(background);

}

return view;

}

}

private class ViewHolder {

TextView tv;

ImageView iv;

}

}

2.2、MyMessage.java中的代码：

[java] view plain copy print ?

package com.cn.daming.draggridview;

import com.cn.daming.adapter.DragMessage;

public class MyMessage extends DragMessage{

public String msg;

}

3、布局文件layout有两个----->

3.1、drag_grid_activity.xml中的代码如下：

[html] view plain copy print ?

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:layout_width="fill_parent"

android:layout_height="fill_parent"

android:orientation="vertical" >

<com.cn.daming.adapter.GragGridView

android:id="@+id/drag_grid"

android:layout_width="fill_parent"

android:layout_height="fill_parent"

android:numColumns="auto_fit"

android:columnWidth="70dp"

android:stretchMode="columnWidth"

android:gravity="center"

android:layout_gravity="center"

android:cacheColorHint="#00000000"/>

</LinearLayout>

3.2、drag_grid_item.xml中的代码如下：

[html] view plain copy print ?

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:background="#FFFFFF"

android:id="@+id/grag_grid_item_view"

android:layout_width="fill_parent"

android:layout_height="fill_parent">

<TextView

android:id="@+id/drag_grid_item_text"

android:layout_width="wrap_content"

android:layout_height="50dp"

android:paddingLeft="5dip"

android:gravity="center"

android:textColor="#ffff00ff"

android:layout_below="@+id/drag_grid_item_image"

android:capitalize="none"

<ImageView

android:id="@+id/drag_grid_item_image"

android:layout_width="50dp"

android:layout_height="50dp"

android:scaleType="center"

</RelativeLayout>

有问题的可以留言，欢迎大家来讨论研究，分享知识，共同进步！

以下是我在开发中遇到问题的参考资料：

http://www.cnblogs.com/qianxudetianxia/archive/2011/06/19/2084886.html

http://lipeng88213.iteye.com/blog/1099621

http://hi.baidu.com/jwq359699768/blog/item/f2caee8741e71131c75cc369.html

源代码下载地址：http://download.csdn.net/detail/wdaming1986/4207350

Android中GridView拖拽的效果,布布扣,bubuko.com

时间： 2024-10-12 13:38:33

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